What Are the Different Types of Evidence and How Are They Used?

Evidence is any material item or information used to establish something is true. It is integral to the judicial tribunal and used in academic writing, scientific and historical research, journalism, and everyday decision-making. Simply put, evidence is the proof that what has been claimed is true and that decisions can be made based on it.

In a legal setting, several types of evidence may be entered to help the court determine the accuracy of a fact, whether a crime was committed, and who was responsible for said crime, and consequently, make decisions and judgments about the case. These include physical, expert, and documentary evidence as well as oral or written testimonies. In certain cases, hearsay may also be admitted as evidence. Evidence plays a crucial role in establishing facts and credibility. 

What Are the Different Types of Evidence?

Several types of evidence are commonly used in legal proceedings and other settings to prove the factuality of a claim. Each type of evidence is important and has several applications depending on the context.

Physical Evidence

Physical evidence refers to tangible items, such as objects, weapons, or documents, that can be presented in court or investigations. Our senses can perceive this type of evidence, that is, it can be seen, touched, or heard. Physical evidence includes fingerprints, footprints, broken glass, weapons, bloodstains, paint chips, or signed contracts.

The major types of physical evidence are trace, biological, and comparative. Trace evidence is small evidence transferred from one object when it comes in contact with another, such as fibers and hair left in a crime scene. Biological evidence includes blood, saliva, semen, and feces. For example, comparative evidence is used in crime scene analysis to determine if two items came in contact with each other. 

Documentary Evidence

Documentary evidence is written or recorded materials used to support claims or arguments, such as emails, contracts, or video recordings. They are tangible evidence containing a record of some kind. Documentary evidence includes contracts, maps, plans, emails, medical records, audio recordings, graphs or drawings, photographs or films, and computer records. 

Due to its nature, documentary evidence must be authenticated before being entered into evidence. In some cases, such evidence may not be allowed into evidence if it is not the document's final version or is considered hearsay.

Testimonial Evidence

Testimonial evidence is statements made by witnesses under oath. Testimonies may be given in person in court or by a signed affidavit. This evidence is based on the credibility of the witness giving the testimony and may not have any physical evidence to back it up. They provide a clear picture, support a narrative, or create a connection between things.

Testimonial evidence may be given by professionals who understand the subject of the case and can give an expert opinion. People who witnessed the crime firsthand also give this type of evidence. 

Testimonial evidence may be tainted by perjury when the witness knowingly lies under oath to influence the outcome of the case. Cross-examination, where lawyers question the witnesses to get more information, is used to verify the credibility of such evidence as inconsistencies, if any, become evident.

Circumstantial Evidence

Circumstantial evidence is indirect evidence that requires an inference to connect it to the facts. In cases where there are no witnesses or definitive physical evidence that ties a specific person to the crime, circumstantial evidence may suggest that the crime happened a certain way or that someone was involved.

Circumstantial evidence uses physical evidence, indirect testimony, scientific evidence, or human behavior. A combination of these may be used to convict someone. For example, prosecutors may use the fact that someone was seen near a crime scene as an indication of potential involvement, especially if that person is connected to the crime (knows or dislikes the victim or uses a similar MO).

Expert Evidence

Expert evidence is testimony or analysis provided by someone with specialized knowledge, such as forensic scientists or medical professionals. The forensic expert giving an expert opinion is expected to do so impartially based on the information provided. Expert testimonies are used in arbitrations, tribunals, and litigations.

Experts are important in complex cases where their technical expertise is required to help the judge and jury better understand the subject. The court screens the experts and ensures that they are qualified, use reliable methods, and that their testimony is relevant to the case. The testimony of an expert may be struck out if it is determined to be misleading.

How Are Different Types of Evidence Used in Court?

The admission of evidence in court is a crucial part of the legal process - it ensures that claims that could determine the outcomes of court cases are verified and factual. Evidence also plays a part in determining whether an accused person is guilty or innocent. Due to its importance, some rules govern how evidence is used in court.

The Role of Evidence in Proving Guilt or Liability

In criminal and civil cases, evidence plays a role in determining if a person charged with a crime is guilty or liable. The standard of proof in criminal cases is a lot higher than in civil cases as the prosecution is required to prove their case beyond reasonable doubt. This means that there must be no counter-theory or loose ends that undermine their presentation of the case. 

Prosecutors in criminal cases typically review all the evidence found at the crime scene - this includes all the physical evidence like blood, bullet casings, fingerprints, and DNA. They also invite witnesses (be they expert witnesses or witnesses who have a firsthand account of the crime) and review related documents like the police report and medical records. Prosecutors present the evidence (physical or circumstantial) to the judge and jury and create a narrative that connects the evidence to a story about the crime. This helps the judge and jury decide if the defendant is guilty.

In civil cases, plaintiffs only have to provide enough evidence that cancels out the defendant's argument - this is known as the preponderance of evidence. Just like in criminal cases, the plaintiff presents the evidence and calls witnesses to stand. They also present a narrative that shows that the defendant is guilty or liable for the crime.

Rules Governing Evidence in Court

There are legal principles that guide the use of evidence in court; these include: 

• Admissibility: This means that evidence must be admissible under the Federal Rules of Evidence (FRE), which provides the guidelines for admitting evidence into federal courts. State courts use similar guidelines. These rules also cover what kinds of evidence can be admitted in criminal and civil cases.
• Relevance: Evidence must be relevant to the case they are being admitted to. Relevance is a key factor in determining if the judge admits a piece of evidence. FRE stipulates that evidence is relevant if it helps to make a fact more or less probable. 
• Authenticity: This means that any evidence entered into court must be authenticated, that is, verified as being what it claims to be. This can be done in several ways, such as by using testimonies or using the evidence’s distinctive characteristics.

Other rules governing evidence include hearsay rules and chain of custody requirements. Hearsay is any statement made in court repeating what someone else had said outside of court and as evidence of the statement's veracity. It happens when someone tries to testify about something they don’t know firsthand. Except for certain exceptions, hearsay is not allowed in court. 

Chain of custody requirements ensures that evidence is not tampered with or contaminated by laying out a series of documentation and procedures that people handling the evidence must follow from their collection at the crime scene to their presentation in court.

How Are Types of Evidence Used in Writing and Persuasion?

Beyond its legal ramifications, evidence also plays a vital role in writing and communication, ensuring that arguments are credible and soundly built. Evidence creates a persuasive and effective message.

Types of Evidence in Writing

Several types of evidence used in writing incorporate facts, examples, statistics, and expert opinions. These include:

• Anecdotal Evidence: This type of evidence uses stories and case studies to support the argument it is making. Anecdotes help you connect with your readers and present your point in a relatable and emotional way; as such, their use can keep the recipient’s attention for much longer.

• Statistical Evidence: Statistics from credible sources can help support any point made in writing. Their matter-of-fact, at-a-glance nature makes statistics very good evidence to use. It is important to use credible sources so that the statistical evidence is not refuted.

• Analogical Evidence: Considered one of the weakest evidence types in writing, analogical evidence compares something unknown with something similar that is known and then draws a conclusion based on that comparison. 

• Testimonial Evidence: Testimonial evidence uses experts' opinions to make its point. Since expert opinion is seen to be above the common man's, it is a good way to add credibility to the argument. It is important to establish the expert's credibility by stating their qualifications and achievements.

• Textual Evidence: This is evidence where an excerpt from a book is used to strengthen the point being made. This may be done using a direct quote, summarizing, or paraphrasing the book.

How to Choose the Right Type of Evidence

In selecting what evidence to use in your writing, you should first and foremost ensure that it is relevant to and supports the point you are making. You want to choose evidence that is clear and easy to understand. It is also important to ensure that the evidence is credible. Ensure you use various evidence types and provide context for the evidence to help the audience understand its relevance.

Whether in the legal world or other fields like writing, evidence is crucial to verifying the facts and ensuring that what was claimed is true. As such, it is vital to ensure that any evidence will be used is accurate and credible. It is important to evaluate the evidence you encounter or use critically.